Agitating device



Jan. 4, 1949. D. s. .STEVENS 2,458,313

v AGITATING DEVICE Filed April 28, 1947 Inventor By Daniel S. Sevens Y Aftorney Patented Jan. 4, 1949 UNITED STATES PATENT OFFICE AGITATING DEVICE Daniel S. Stevens, Chicago, Ill.

Application April 28, 1947, Serial No. 744,369

This invention relates to electric agitating devices, particularly such devices as may be used in hospitals, biologic laboratories or the like for agitating one or more hemocytometer pipettes.

It is one of the objects of the present invention to provide an agitating device of the above mentioned character into which the pipette may be easily and rapidly placed or from which it may be easily and rapidly removed. It is a further object of the `present invention to provide an agitating device oi the above mentioned character which will produce only an exceedingly small amount of noise in its operation. It is a further object of the present invention to provide an agitator oi the above mentioned character wherein the amplitude of vibration can be easily adjusted. It is a still further object of the present invention to provide an agitating device which is simple and economical of construction and yet sturdy enough to withstand all of the rough usage to which devices of this type may be subjected.

The attainment of the above and further objects of the plesent invention will be apparent from the following specification taken in conjunction with the accompanying drawingr forming a part thereof.

In the drawing:

Figure 1 is a yplan view of a device embodying the present invention, said 'view being partially in section by a section taken along the line I--I of Figure 2;

Figure 2 is a sectional View taken along the line 22 of Figure 1;

Figure 3 is a sectional view taken along the line 3-3 of Figure 1;

Figure 4 is a reduced size bottom view of the device; and

Figure 5 is a side view of a modified construction.

Reference may now be had more particularly to the drawings wherein like reference numerals designate like parts throughout.

The vibrator of the present invention is indicated in general by the reference numeral I and consists in general of a circular base '2 of rubber having on the under side thereof two rectangular grooves 3 and 4 at right angles to one another. In the groove 4 is laid a. brass strip 5 and in the groove 3 is laid a brass yoke I5, the two being connected together by screws 1`I. The yoke 6 has arms 8-8 that extend upwardly through rectangular openings 9 in the rubber base 2. The strip 5 has an upstanding arm I2 that also extends through an opening in the base 2. An electric switch I3 of the snap action or toggle type is 6 Claims. (Cl. 259-75) mounted on the arm I2 as by extending through an opening in the arm and being locked thereto by a set of lock nuts on opposite sides of the arm I2.

Between the arms 8 8 is mounted a vibrating type electro magnet I4 having a laminated iron core I 5 and an electric winding coil I6. The core I5 lies between the arms 88 and is of the same width as the arms 8*8 and is held in place by a pair oi screws 2li-28 that pass through holes 2 I--I in the arms 8--8 and each of which carries a pair of discs or washers 22--22 which discs are clamped against the opposite sides of the core and against the opposite sides of the arms 8 8 by the head of the screw at one end and a lock nut 23 at the other end.

An armature II is provided for the electro magnet.Y The armature comprises a flat strip of spring metal I8 comprising an iron leaf spring, to which are secured one or more soft iron strips I9 which are on the portion of the strip I8 that @verlies the iron core I5 of the electro magnet,

' to increase the magnetic pull by reducing the reluctance of the armature. The armature I'I is secured to one of the arms 8 by means of a screw 25. An adjustable thumb screw 26 has a shank which extends through an oversize hole in the armature and threads into one of the arms 8. The thumb screw 26 acts as a limiting stop to limit the upward movement of the armature II when the armature is manually handled roughly. The lowering vibratory movement of the armature I'I is limited by a ring of rubber or other elastic material which surrounds the shank of the screw 26. In assembly of the device, a rubber ring is selected of such thickness that the vibrating arm strikes the ring lightly on its lowering vibratory movement. Since the ring 21 is made of rubber it acts as a noise reducer or silencer. The vibrating arm striking lightly against the rubber ring gives an increased bounce to the pipette holder 3i). By thus increasing the agitatingr efficiency less power need be supplied to the vibrating arm by the electro magnet. This further reduces the noise generated by the device. rIhe problem of noise is important since one or a group of these shakers are frequently operated for long periods in hospitals,

A pipette holder 38, of rubber or the like, is secured to the free end oi the armature by two screws 3I-3I. The upper side of the pipette holder has two longitudinally extending slots 32-33 therein each of which has an enlargement 34 at one end. Each enlargement is of a depth greater than that of the slot and may actually extend entirely through the rubber holder 30. A pipette, indicated at 36, may be dropped into the slot 32 or 33 with the head 31 of the pipette, which constitutes a diluting chamber, resting in the enlargement 34. The enlargements 34 may be of different sizes to receive pipette heads of diierent diameters. The pipette has the usual stirring bead 39 in the diluting chamber. During the vibration of the armature the pipette rests as a free body within the slot and the head 31 prevents the pipette from slipping out of the holder 30. The pipette is thus held in a simple manner without the use of clamps or the like, and may quickly be inserted in or removed from the holder. The depth of each slot is so great that upon vibration and shaking of the pipette the pipette will nevertheless not be thrown upwardly an amount sufficient to throw it out of the holder 30 but the pipette will bounce and turn in the holder.

The switch I3 is connected in series with the winding I6 vof the lelectro magnet. The electro magnet here shown is an alternating current magnet which when connected to a source of sixty cycle alternating current will cause the armature to vibrate.

An inverted cup-shaped cover 40, of rubber, overlies the top of the base 2 and encloses the vibrator. The bottom of the rim of the cup rests on the base 2, and the cup is held in place by a pair of screws 42 that pass through the top of the cup and pass into the base 2 and are threaded into the brass strip 5.

The cylindrical Wall of the inverted cup-shaped cover 40 has a slot 46 therein through whichthe armature extends and another slot 41 displaced 90 from the slot 46 and through which the toggle of the switch I3 extends.

The bottom of the base l has three rubber legs 44 integral therewith which serve to space the base above a surface upon which the vibrator rests.

The structure shown in Figures l, 2 and 3 is adapted for mounting on a horizontal base. If desired the agitating device may be designed for mounting on a vertical wall instead of on a horizontal base. To accomplish this result it is merely necessary to bend the right hand end of the leaf spring armature I1 -at right angles to the position illustrated inY Figure 2, and then the structure may be mounted on a vertical wall. This is illustrated in Figure 5 wherein a vertical wall is indicated by the reference numeral B0 and the agitator l is mounted on the vertical wall. The agitator l differs from the agitator previously described only in that its armature spring i8', which corresponds to the armature spring l 8, is bent at its upper end to provide a substantially horizontal portion 62 at right angles to the vertical portion. In other respects this vibrator is the same as that previously described and similar reference numerals have been used.

The'novel construction of this device provides new and useful features important to the technique of shaking blood-diluting pipettes. The pipette rests in the holder member as a free body. The vibratory kmotion causes the stirring bead to move about in all directions in the diluting chamber. This motion in itself is sufficient to disperse the blood cells throughout the diluting fluid. However, since the slot in the holder is usually made larger than the corresponding dimension of the pipette, the pipette is free to bounce lightly and thus slowly rotate. This increases the .eiiiciency of agitation sincethe blood cells, being heavier than water, tend to settle downward.

In compliance with the requirements of the patent statutes I have here shown and described a few preferred embodiments of my invention. It is, however, to be understood that the invention is not limited to the precise constructions here shown, the same being merely illustrative of the principles of the invention.

What I consider new and desire to secure by Letters Patent is:

1. A clinical agitator comprising a fiat leaf spring rigidly mounted at one end and adapted to be set in vibration, and the opposite end being free, and a pipette holder on and secured to the opposite end to be Vibrated thereby, said holder comprising a mass of rubber having a pipettereceiving slot extending across the top thereof, said slot being open at the top and of a depth substantially greater than its width and said slot havingV a portion of a greater width thanthe rest of the slot for receiving the bulbous portion of a pipette, the slot being of sufficient depth and width so that a pipette inserted in the slot is free to bounce and turn therein during agitation thereof by vibration of the leaf spring.

2. A clinical pipette agitator comprising a vibratory armature, a rubber pipette holder mounted thereon and agitated thereby, said holder be'- ing adapted to support a pipette and saidholder having rrubber means looselyk embracing the pipette to permit free turning and bouncing of the pipette with respect to the rubber holder as the holder is vibrated by the armature, said loose embracing means conning the pipette against rolling off of the holder, the rubber of the holder including the embracing means serving to cushion the Ibouncing of the pipette in the vibrator.

3. A clinical pipette agitator comprising a vibratory armature, a rubber pipette holder mounted thereon and agitated thereby, said holder being adapted to support a pipette and said holder having rubber means loosely embracing the pipette to permit free turning and bouncing of the pipette with respect to the rubber holder as the holder is vibrated by the armature, said loose embracing means confining the pipette against rolling on of the holder, the rubber of the holder including the embracing means serving to cushion the bouncing of the pipette in the vibrator, and a rstop limiting the vibration oi the armature in one direction, said stop being of rubber to reduce vibration noise.

4. A clinical pipette agitator comprising a vertically extending vibratory armature having a right angle bend at its upper end to provide a seat for a holder, a rubber pipette holder mounted on the seat and vibrated by the armature, said holder being adapted to support a pipette and said holder having rubber means loosely embracing the pipette to permit freeturning and bouncing of the pipette with respect to the rubber holder as the holder is vibrated by the armature, said loose embracing means confining the pipette against rolling off of the holder, the rubber of the holder including the embracing means serving to cushion the bouncing of the pipette yin the vibrator;

5. In a vibrating clinical agitator for a hemocytometer pipette having a bulbous diluting chamber from which extend a pair of aligned tubes of substantially less diameter than that of the bulbous chamber, a pipette'holder adapted to supporta pipette while permitting free rolling and bouncing of the :pipette-,Withrrespect tothe holder as the holder is vibrated, said holder having portions for loosely embracing each of the arms on opposite sides of the bulbous chamber, said loosely embracing portions on one side of the bulbous chamber being spaced from the loosely embracing portions on the other side of the bulbous chamber by an amount greater than the diameter of the chamber to permit longitudinal sliding of the pipette to an amount limited by the engagement of the bulbous chamber with the loosely embracing portions of one of the other of the two arms, said loosely embracing portions of at least one of the arms being separate from one another at the top of the holder, those portions of the pipette holder that come into contact with the pipette during agitation thereof being of rubber to cushion the pipette as it bounces and moves in the holder and to reduce the noises produced by such bouncing and movement.

6. A vibratory type clinical pipette agitator having a pipette holder for receiving a pipette having a bulbous diluting chamber from which extend a pair of aligned tubes of substantially less diameter than that of the bulbous chambers, and means for vibrating the holder, characterized by the fact that the pipette holder is adapted to support a pipette as a free body and permit bouncing of the pipette with respect to the holder under the vibrating action thereof, the holder including means for supporting a pipette in a hori- 6 zontal position, and including two sets of embracing walls extending upwardly from the supporting means, the sets being spaced from one another to permit positioning the bulbous portion of the pipette between the sets and with the embracing walls of each set spaced apart for embracing the pipette loosely to confine it on the holder but to allow a limited amount of free longitudinal movement of the pipette in the holder as it bounces in the holder under the vi Ibrating action thereof, the height to which the embracing walls extend above the pipette supporting surface being substantialy greater than the space between the walls of a set to guide the pipette in its bouncing movement.

DANIEL S. STEVENS.

REFERENCES CITED The following references are of record in the .file of this patent:

UNITED STATES PATENTS Number Name Date 1,456,147 Putnam May 22, 1923 1,739,349 Blain Dec. 10, 1929 1,891,486 Wahl Dec. 20, 1932 1,918,018 Clars July 11, 1933 1,986,038 Zielke Jan. 1, 1935 2,088,304 Mizzy July 27, 1937 

